1) Field of the Invention
The present invention relates to a device for processing output signals from a photo-diode, more especially to a device for pairing up the elements of a light-emitting diode and a photo-diode, converting a digital output signal with the photo-diode element and correcting the signal wave shape.
2) Description of the Prior Art
Accordingly, the elements of a light-emitting diode (LED) and a photo-diode have been extensively applied to the insolated circuit for isolating signal transmission, remote-controlling signal transmission, interrupting circuit, being an emitter or receiver of a photoelectric encoder in an encoding wheel; for any of the abovementioned applications, the elements of the LED and the photo-diode must be used in pairs; however, influenced by the factors of manufacturing procedure, material, the chip package and the light case, the paired result of every LED and photo-diode is not always desirable and extremely subjected to have difference due to the nature or the long-term deterioration of the elements of the LED and the photodiode; therefore, the output analog signal from the element of the photo-diode might have deviation or distortion; as shown in FIG. 6, the time (T) of the highest electric potential (the positive semi-cycle crest value) in a signal (A) is too long, so the wave deforms, deviates and distorts; when being converted to a digital signal, as shown in FIG. 6, signal (B) also has same the shortcomings of signal deviation and distortion; thereby, the wave shape of signal (B) is not symmetric and that disadvantageously affects applying the photo-diode to a circuit.
Therefore, before pairing up the LED and the photo-diode, the industrials have to first use an apparatus for testing, then categorize them before applying them to the circuit product on the production line; that is time and labor consuming; furthermore, to manually test the pairing-up will relatively increase the manufacturing cost of the LED and the photo-diode and that does not meet the effect of industrial utilization.
Therefore, the primary objective of the present invention is to provide a device for processing output signals from a photo-diode which comprises a comparative conversion circuit, a reference circuit, a feedback logic unit and a programmable adjusting resistor to arbitrarily pair up the photo-diode without manually testing and matching.
Another objective of the present invention is to provide a device for processing output signals from a photo-diode, wherein, the reference circuit and the feedback logic unit can precisely and automatically feed back and provide the wave electric potential and time of an analog output signal of the photo-diode element to more precisely correct the wave of the analog output signal of the photo-diode through a precise feedback signal.
Yet another objective of the present invention is to provide a device for processing output signals from a photo-diode, wherein, the said programmable adjusting resistor can be controlled and driven by a digital signal to precisely and automatically correct the analog and digital output signal of the photo-diode to make the wave of the digital output signal of the photo-diode acquire a closed loop feedback adjustment.
For achieving the abovementioned objectives, the present invention of a device for processing output signals from a photo-diode comprises a comparative conversion circuit, a reference circuit, a feedback logic unit and a programmable adjusting resistor; the said comparative conversion circuit converts an analog output signal generated from a photo-diode to a square wave digital signal; the reference circuit obtains a reference signal by capturing the analog output signal from the photo-diode, feeds it back to the said feedback logic unit; the said feedback logic unit times the high or low electric potential of the reference signal; when the low electric potential time is too long, the feedback logic unit emits digital adjusting signal to the programmable adjusting resistor to adjust the entire electric potential and the wave crest value time of the analog output signal of the photo-diode to make the final output square wave digital signal of the comparative conversion circuit acquire a symmetric wave correction.
To enable a further understanding of the detail structure and the operation of the present invention, the brief description of the drawings below is followed by the detailed description of the preferred embodiment.